#include <stdio.h>
#include <string.h>
#include<ctype.h>
int main()
{	 	        	
    long a[60];
    int len, dig=0, c, n;
    int i = 0;
    char str[20];
    printf("please input a string:\n");  //1
    scanf("%s", str); //1
    len = strlen(str);
    for (i = 0; str[i] != '\0'; i++) //1
    {	 	        	
        dig = isdigit(str[i]); //1
        if (dig == 0) //1
            break; //1
    }
    if (dig != 0) //1
    {	 	        	
        printf("please input the multiplicand:\n");
        scanf("%d", &n);
        for (i = 0; i < len; i++) //1
            a[i] = str[len - i - 1] - '0'; //1
        c = 0;
        for (i = 0; i < len; i++ ) //1
        {	 	        	
            c += a[i] * n; //1
            a[i] = c % 10; //1
            c /= 10;
        }
        ((a[i] = c) > 0) ? len++ : 0; //1
        len--;
        for ( ; len >= 0; len--)
            printf("%ld", a[len]); //1
    }
    else
    {	 	        	
        printf("you inputing the string  is not a digit string.\n");
    }
    return 0;
}